After making sure the curtains were pulled closed, Knox turned on all the lights and started to make his way through the flat, room by room. It looked like it had never been lived in. Everything apart from the most basic furniture had been removed. Knox wondered what had happened to the men’s possessions. They must have had more clothes than the ones they’d been found in, more bits and pieces of everyday life that would have helped him build a picture of who they were, what they were doing, and why they died. He’d hoped for a treasure trove of clues, but he found nothing.

He left the small office until last. It was as bare as the rest of the flat. The desk was clear, the boxes gone, the bookcase still empty. He was about to give up, until he realised that one side of the large set of shelves wasn’t quite flush with the wall. It was only off by less than half an inch, a small enough gap for most people to miss, but it caught his attention.

He squinted behind it, but couldn’t see anything in the narrow, dark void. So he grabbed both sides and started to walk it away from the wall. He heard a low thud as something fell to the floor, finally free from its hiding place. Knox reached behind the case and pulled out what he’d dislodged. It was another bundle of pages covered in equations. But these ones weren’t made up of nonsense symbols. They were letters and numbers, maths he could recognise. And, in the middle of the bundle, were two brand new Swiss passports.

Chapter 23

Chapter 23

The sun was on its way back up into the sky when Valera woke up. For the briefest second her mind allowed her some peace before it reminded her where she was and what had happened. Her stomach cried out again for food, but she had no more to give it. All she could do was get up, stretch out her tired body, and wait for different kinds of pain to smother her hunger.

She shouldered her pack, picked up Ledjo’s in her arms, and started walking again. She didn’t know how long she’d been asleep, but even though the sun was already getting higher the air was still cool. She might only have been unconscious for a few hours. She stopped at pools and small creeks for water, but with nothing to eat she quickly became light-headed. ‘